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BACKGROUND: The treatment of cervical spondylosis with total disc replacement can retain the range of motion of the cervical lesion segment and can effectively improve the symptoms of cervical spondylosis with sympathetic symptoms. OBJECTIVE: To investigate the clinical efficacy of total disc replacement for cervical spondylosis with sympathetic symptoms. METHODS: Retrospective analysis was made on 56 patients with cervical spondylosis with obvious sympathetic symptoms such as dizziness and headache who were operated on from December 2018 to December 2021. The sagittal parameters of the cervical spine before, 3 months after surgery and at the last followup were observed and compared, including cervical sympathetic symptom score and Japanese Orthopaedic Association Scores, operation segment angle, C2- C7 Cobb angle, C2-C7 sagittal vertical axis and T1 slope. The correlation between the changes in sympathetic symptoms and Japanese Orthopaedic Association Scores before and after surgery and the changes in cervical sagittal parameters before and after surgery was analyzed. RESULTS AND CONCLUSION: (1) All patients showed improvement in sympathetic symptoms after surgery, and the sympathetic symptom scores and Japanese Orthopaedic Association Scores were significantly improved at 3 months and at the last follow-up compared with those before surgery (P < 0.05), but Japanese Orthopaedic Association Scores did not show significant differences at the last follow-up compared with those at 3 months after surgery (P > 0.05). (2) The cervical sagittal parameters increased at 3 months and at the last follow-up compared with those before surgery, but not at the last follow-up compared with those at 3 months after surgery (P > 0.05). (3) The pre- and post-operative change values of sympathetic symptom scores significantly correlated with the preand post-operative change values of operation segment angle and C2-7 Cobb angle (P < 0.05). (4) The results indicate that total disc replacement has a good effect in the treatment of cervical spondylosis with sympathetic symptoms, which is conducive to restoring the sagittal parameters of the cervical spine and alleviating the sympathetic symptoms of patients. [ABSTRACT FROM AUTHOR]

BACKGROUND: At present, there are many surgical methods for the treatment of lumbar disc herniation, and the therapeutic effects have their own advantages. Although there are many meta-analyses to compare the therapeutic effects of the two surgical methods, there is no comparison of the therapeutic effects of several surgical methods. OBJECTIVE: To compare the differences of different surgical methods in the treatment of lumbar disc herniation by network meta-analysis. METHODS: PubMed, Embase, Cochrane Library, Ovid and CNKI were searched, and randomized controlled trials or retrospective studies on different surgical methods for the treatment of lumbar disc herniation were collected. According to the inclusion and exclusion criteria established in advance, the quality of included randomized controlled trials was evaluated, and the data were analyzed by STATA 15.0 software. RESULTS AND CONCLUSION: A total of 42 studies, 5 156 patients and 9 surgical treatments were included. Surgical treatments contain total disc replacement, lumbar disc fusion, standard open discectomy, microendoscopic discectomy, microdiscectomy, percutaneous endoscopic lumbar discectomy, chemonucleolysis, automatic percutaneous lumbar discectomy and percutaneous laser disc decompression. The results of network meta-analysis showed that (from best to worst): (1) There was no significant difference in leg pain relief, and the rank probability was percutaneous laser disc decompression > microendoscopic discectomy > percutaneous endoscopic lumbar discectomy > standard open discectomy > microdiscectomy > lumbar disc fusion > total disc replacement. (2) There was no significant difference in low back pain relief, and the rank probability was total disc replacement > lumbar disc fusion > microendoscopic discectomy > percutaneous endoscopic lumbar discectomy > microdiscectomy > percutaneous laser disc decompression > standard open discectomy. (3) There was no significant difference in Oswestry disability index scores, and the rank probability was microendoscopic discectomy > percutaneous endoscopic lumbar discectomy > standard open discectomy > microdiscectomy > total disc replacement > lumbar disc fusion. (4) There were some statistical differences in the success rate, and the rank probability was total disc replacement > lumbar disc fusion > microendoscopic discectomy > percutaneous endoscopic lumbar discectomy > standard open discectomy > percutaneous laser disc decompression > microdiscectomy > chemonucleolysis > automatic percutaneous lumbar discectomy. (5) There was no significant difference in reoperation rate, and the rank probability was total disc replacement > lumbar disc fusion > microdiscectomy > microendoscopic discectomy > standard open discectomy > percutaneous endoscopic lumbar discectomy > percutaneous laser disc decompression > chemonucleolysis > automatic percutaneous lumbar discectomy. (6) There were some statistical differences in incidence of complications, and the rank probability was percutaneous endoscopic lumbar discectomy > automatic percutaneous lumbar discectomy > standard open discectomy > microdiscectomy > percutaneous laser disc decompression > microendoscopic discectomy > total disc replacement > lumbar disc fusion > chemonucleolysis. Results suggested that microendoscopic discectomy and percutaneous endoscopic lumbar discectomy are effective in all aspects. Disc replacement and lumbar disc fusion are the best in success rate of operation. Chemonucleolysis is poor in success rate of operation, reoperation rate and complications rate. Percutaneous automatic discectomy is poor in success rate of operation and reoperation rate. [ABSTRACT FROM AUTHOR]

Anterior cervical discectomy and fusion (ACDF) has achieved good clinical results since it was used in clinic, and is considered as the gold standard for the treatment of cervical spondylosis. However, more and more attention has been paid to adjacent segment degeneration(ASDeg) after fusion, and the debate about its pathogenesis is mainly focused on the bio-machanical stress changes of adjacent segments caused by fusion and the result of the natural aging process. The occurrence of ASDeg after fusion seriously affect the med-and long-term outcome of surgery, and some patients even need secondary surgery. In order to reduce or even avoid the occurrence of ASDeg, many new techniques have emerged in clinic, such as artificial disc replacement with preservation of motor segments, emerging cell transplantation technology and so on, but the clinical effect still needs to be confirmed by a large number of studies. Therefore, finding the risk factors of ASDeg after fusion is of great significance for fusion surgery on the clinical work. At present, there is still no unified overview of the research on the risk factors of ASDeg. This article will review the research progress and corresponding countermeasures of the risk factors of ASDeg after ACDF, in order to guide the clinical application.

The modern surgical treatment of cervical degenerative disc disease can be traced back to the advent of anterior cervical decompression and fusion.With the emergence of fusion-related complications,different scholars have promoted the gradual transformation of cervical degenerative disc diseases from "fusion fixation" to "non-fusion reconstruction" through in-depth fusion with materials science,engineering mechanics and other disciplines.The innovation of this treatment concept is consistent with the original intention of "structural remodeling,functional reconstruction,maximum repair and reconstruction of the morphology and function of skeletal muscle system" in orthopedic bionic treatment,which is essentially in line with the "bionic alternative therapy" in orthopedic bionic therapy.This paper focuses on the surgical treatment of cervical degenerative disc diseases,reviews the development history of artificial cervical disc replacement,analyzes the evolution from orthopedic biomimetic therapy,and explores a new direction for the design of artificial cervical disc prostheses and the treatment of cervical degenerative disc diseases in the future.

Objective: To investigate the influence of the preoperative factors on the segmental range of motion (ROM) during long-term follow-up after artificial cervical disc replacement (ACDR), so as to further improve the selection of surgical indications for ACDR. Methods: Retrospective analysis was performed on 71 patients with cervical degenerative diseases who underwent single-segment Bryan ACDR in Beijing Jishuitan Hosptial from December 2003 to December 2008, and a 10-year clinical follow-up was conducted. Among the patients, 44 were males and 27 were females, with a mean age of (45±8) years at operation. The mean follow-up time was (129±14) months. Preoperative and follow-up imaging evaluation including measurement of the segmental range of motion (ROM) by cervical X-ray, and preoperative height of intervertebral space was measured by cervical lateral X-ray. According to CT and coronal reconstruction, the grade of paravertebral ossification (PO) was assessed. Clinical symptoms assessment including the Japanese Orthopaedic Association scoring (JOA), the Neck Disability Index (NDI) evaluation was performed preoperatively. Multivariate logistic regression analysis was used to analyze the influencing factors of the range of motion of the surgical segment during follow-up. The best cut-off value was calculated by receiver operating characteristic (ROC) curve. Results: The preoperative and follow-up ROM at the operated segment was 9.7°±4.5° and 8.7°±5.4°, respectively ( P >0.05). Univariate analysis revealed that the postoperative segmental ROM was not significantly correlated with the factors including the surgical level, gender, age, and preoperative clinical diagnosis (1: Radiculopathy; 2: Myelopathy; 3: Mixed type), preoperative segmental ROM, preoperative JOA score and preoperative NDI score (all P >0.05), and was significantly correlated with imaging diagnosis (1: cervical disc herniation; 2: degenerative cervical stenosis), preoperative PO grade (both P <0.05). The multi-factor analysis showed that preoperative segmental ROM ( OR =1.228, 95% CI :1.012-1.489, P <0.05) and PO grade ( OR =0.190, 95% CI : 0.085-0.424, P <0.05) had significance in the overall test, but imaging diagnosis had no significance in the overall test ( P >0.05). The optimal cutoff value of preoperative segmental ROM and PO grade was 9.185° and grade 2.5 assessed by ROC curve, and the area under the ROC curve was 0.86 and 0.72, respectively. Conclusions: ACDR surgery can achieve satisfactory long-term effects for patients with nerve root type, spinal cord type and mixed type cervical degenerative diseases, and effectively retain the overall ROM of the cervical spine and the ROM of replacement segments. Patients with good preoperative segmental ROM and lower PO levels have a greater chance of obtaining good segmental ROM in the long-term postoperatively.

Objective: To compare the clinical effects of different anterior surgical methods in treating single segment cervical disc herniation., Methods: The clinical data of 46 patients with single-segment cervical disc herniation underwent surgical treatment from September 2013 to September 2018 were retrospectively analyzed. The patients were divided into three groups according to different surgical methods. Among them, 23 patients in the anterior percutanousendomic cervical dissection (APECD) group, there were 8 males and 15 females, aged (47±3) years old, prominent segments were C 3,4 of 1 case, C 4,5 of 6 cases, and C 5,6 of 16 cases;10 patients in cervical disc replacement(CDR) group, there were 4 males and 6 females, aged (46± 3) years old, prominent segments were C 3,4 of 1 case, C 4,5 of 6 cases, C 5,6 of 3 cases;13 patients in transcervical anterior cervical disc fusion (ACDF) group, there were 8 males and 5 females, aged (53±2) years old, protruding segments were C 3,4 of 1 case, C 4,5 of 3 cases, C 5,6 of 9 cases. The operation time, intraoperative blood loss, and length of hospitalization were compared among three groups;visual analogue scale (VAS) and Japanese Orthopaedic Association(JOA) score were used to evaluate the clinical efficacy., Results: All 46 patients were followed up for 12 to 24 (17.57±3.15)months. The follow-up time of APECD, CDR, ACDF groups were (17.30±3.25), (17.80±3.16), (17.85±2.88) months, and operation time were (95.48 ±13.85), (58.50±7.09), (76.00±15.72) min, respectively, there were no significant differences in follow-up time and operation time between two groups( P >0.05). The intraoperative blood loss of APECD, CDR, ACDF groups were (80.00±20.22), (82.60±7.20), (121.54±18.75) ml, there was significant difference between CDR group and ACDF group ( P <0.05);and there was no significant difference between other groups ( P >0.05). The length of hospitalization was (6.95±1.50) days in APECD group, (6.60± 0.80) days in CDR group, (6.54±0.75) days in ACDF group, and there was no significant difference between two groups ( P > 0.05). At the latest follow up, VAS scores were decreasedfrom preoperative 6.78±0.83 to 2.57±0.65 in APECD group, decreased from 5.70±0.78 to 2.00±0.45 in CDR group, decreased from 6.77±0.42 to 1.38±0.49 in ACDF group. The JOA scores at final follow-up were increased from 8.91±0.97 to 13.04±1.40 in APECD group, and the improvement rate of (65±15)%;increased from 11.50±1.20 to 14.90±1.14 in CDR group, and the improvement rate of (76±19)%;increased from 8.54±0.93 to 14.00±0.96 in ACDF group, and the improvement rate of (74±8)%;there was significant difference in improvement rate between APECD group and CDR group ( P <0.05). At final follow-up, the activities of the responsible segment in APECD group and CDR group were well preserved and improved ( P <0.05). In the APECD group, the symptoms of two cases recurred during the mid-term follow-up (4 months and 6 months after surgery), one of which improved after strictly conservative treatment;the other one received ACDF surgery a second time, and the postoperative follow-up effect was satisfactory., Conclusion: The three anterior surgical approaches can achieve satisfactory clinical results for the treatment of single-segment cervical disc herniation. However, the improvement rate of the CDR group and the activity of the retained responsibility segment are better than those of the other two groups. APECD surgery may have recurrence.

Heterotopic ossification(HO) and progressive bone formation(PBF) are main factors affecting the motion ability of target segments after cervical artificial disc replacement(CADR).The severity of pre-operative degeneration of target segment is the most important factor in the occurrence and progression of HO and PBF. The occurrence and progression of HO and PBF can be reduced basically through the improvement of degeneration evaluation system for intervertebral disc (including height, range of motion and osteophyte formation), uncovertebral joint and facet joint and standardization of surgical indication. The application of new anatomical prosthesis and improved surgical technique are also important factors to reduce the occurrence and development of HO and PBF.

Objective: To investigate the clinical effect of anterior cervical Hybrid surgery in the treatment of cervical degenerative diseases (CDD) and observe the incidence of heterotopic ossification of disc replacement segment at 1 year after surgery., Methods: From January 2015 to April 2018, 35 patients who received anterior cervical hybrid surgery met the inclusion and exclusion criteria and the complete clinical follow up data were analyzed retrospectively. Complete imaging follow-up data were obtained from 24 patients. There were 15 males and 20 females, aged from 39 to 70(55.57±7.73) years old. The amount of bleeding was for 20 to 100 (40.29±18.39) ml, and the hospitalstay was for 4 to 28(11.03±4.63) days, and the follow-up time was(12.97±1.36) months. Clinical outcomes were assessed by the Tanaka Yasushi cervical spondylitis symptom scale 20 score (YT20), and Japanese Orthopaedic Association (JOA) score. The occurrence of heterotopic ossification after Hybrid surgery was evaluated by X-ray according to McAfee standard one year after operation. Patients with or without heterotopic ossificationwere divided into two groups and their clinical effects were compared., Results: At the final follow up, the mean YT20 score and JOA score were significantly higher than those before operation (P <0.05), and the average improvement rate of JOA was (70.66 ±0.44)%. One year after operation, the heterotopic ossification occurred in 10 of 24 segments, with incidence of 41.70%(10/24), including 29.20% in gradeⅠand 12.50% in gradeⅡ. The results of clinical efficacy comparison between patients with and without heterotopic ossification were as follows:there was no significant difference in JOA score before and after operation ( P >0.05);there was no significant difference in YT20 score before operation ( P >0.05), and YT20 score in patients with heterotopic ossification was significantly lower than that in patients without heterotopic ossification( P <0.05)., Conclusion: The short-term clinical effect of Hybrid surgery is satisfactory for cervical degenerative diseases, and the cause of heterotopic ossification still needs tobe further explored.

Objective: To explore the influence factors of anterior bone loss (ABL) after cervical disc arthroplasty (CDA) and effects of ABL on the clinical and radiographic outcomes., Methods: One hundred and fifty-five patients who underwent single-level Prestige-LP CDA between January 2008 and December 2017 and met the inclusive criteria were enrolled in the study. Perioperative data of patients were collected. The Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), and the visual analogue scale (VAS) score were used for clinical outcomes evaluation. Radiographic parameters including cervical lordosis, C 2-7 range of motion (ROM), disc angle, segmental ROM, and the lengths of the upper and lower endplates were assessed on the X-ray films. Device-related complications, including ABL, subsidence, radiographic adjacent segment pathology, and heterotopic ossification, were recorded. Univariate analysis was used to analyze the related factors, and logistic regression analysis was used to screen the influence factors. Patients were grouped according to whether ABL occurred after operation, and the differences in clinical and imaging evaluation parameters were compared., Results: There were 94 cases (60.6%) in the ABL group and 61 cases (39.4%) in the non-ABL group. Univariate analysis showed the significant differences in age, body mass index (BMI), and intraoperative blood loss between the two groups ( P <0.05). However, there was no significant difference in gender, bone mineral density (T value), preoperative blood calcium level, preoperative blood phosphorus level, preoperative alkaline phosphatase level, operative segment, operative time, and follow-up time between the two groups ( P >0.05). Multivariate analysis showed that the age and BMI were influence factors for ABL after CDA ( P <0.05). The JOA score, NDI, and VAS score significantly improved in both groups at 3 months after operation ( P <0.05), and the scores were further improved at last follow-up ( P <0.05). There was no significant difference in JOA score, NDI, and VAS score between the two groups before and after operation ( P >0.05). The preoperative cervical lordosis was significantly smaller in the ABL group than in the non-ABL group ( t =-2.402, P =0.018). At last follow-up, the segmental ROM was significantly greater in the ABL group than in the non-ABL group ( P <0.05), and the lengths of the upper and lower endplates were less in the ABL group than in the non-ABL group ( P <0.05). No significant difference in the other radiographic parameters between the two groups were found ( P >0.05). Prosthesis subsidence occurred in 5 cases (3.2%), including 3 cases in the ABL group and 2 cases in the non-ABL group; the difference between the two groups was not significant ( P =1.000). Heterotopic ossification occurred in 67 cases (43.2%), including 32 cases in the ABL group and 35 cases in the non-ABL group; the difference between the two groups was significant ( χ 2 =8.208, P =0.004). High-grade heterotopic ossification was detected in 26 cases (13 cases in the ABL group and 13 cases in the non-ABL group). Twenty-nine cases (18.7%) had radiographic adjacent segment pathology, including 15 cases in the ABL group and 14 cases in non-ABL group; the difference between the two groups was not significant ( χ 2 =1.190, P =0.276)., Conclusion: The incidence of ABL after CDA was relatively high, which mainly occurred within 3 months after operation, and no longer progressing with stable radiographic features after the first 12 months. Age and BMI were independent influence factors for ABL. ABL does not affect the clinical outcomes but may preserve more ROM of prostheses.

Objective: To investigate the clinical outcomes and radiographic results of artificial cervical disc replacement (ACDR) for cervical adjacent segment disease (ASD). Methods: The clinical data of 28 patients with single-segment cervical ASD treated with ACDR in Xi 'an Honghui Hospital from December 2013 to July 2016 were retrospectively analyzed. There were 19 males and 9 females with a mean age of (46±7) years (36-63 years). Preoperative, postoperative 1 month and postoperative 24 months of clinical and radiographic outcomes were recorded and compared. The clinical outcome mainly includes Japanese orthopedic association (JOA), Neck Disability Index (NDI%), Odom score and complications. Imaging assessment mainly included range of motion (ROM) of cervical spine, surgical segment ROM, Cobb angle of surgical segment, degree of adjacent disc degeneration, heterotopic ossification, and prosthesis related image parameters. Results: In terms of clinical outcome, the average JOA score was 12.7±1.5 before surgery, 14.0±1.0 one month after surgery, 15.8±0.9 24 months after surgery, and the improvement rate of JOA was 75%±19%. The mean NDI% was 27.0%±2.8% before surgery, 20.5%±1.6% one month after surgery, and 15.3%±2.8% 24 months after surgery; the difference before and after treatment was statistically significant ( F= 159.101, P< 0.01). Twenty patients were classified with excellent Odom score and 8 patients with good Odom score at the final follow-up. The total ROM of cervical spine, operation segment ROM, operation segment Cobb angle were all improved significantly after the operation ( F= 4.633, 6.063, 26.952, all P< 0.05). There was a statistical difference in Miyazaki classification between adjacent discs above ACDR and below the fusion segment 24 months after surgery (μ(c)=2.12, P= 0.034). The incidence of heterotopic ossification was 14.3%. The results of displacement degree of prosthesis were as follow: coronal plane (0.30±0.11) mm, sagittal plane (0.28±0.10) mm; subsidence of the prosthesis: (0.27±0.09) mm. No prosthesis loosening was observed. Conclusions: The clinical outcome of revision of cervical ASD by ACDR is satisfactory. The risk of intervertebral disc degeneration in adjacent segments is significantly lower than that of ACDF due to the presence of certain motor function postoperatively.

Objective: To compare the long-term clinical effect and imaging results of Bryan artificial cervical disc replacement (ACDR) and anterior cervical discectomy and fusion (ACDF) and to explore whether ACDR can reduce the occurrence of postoperative adjacent segment degeneration (ASD) in the treatment of degenerative cervical spondylosis. Methods: It was a retrospective study. Total of 60 patients with degenerative cervical spondylosis, who had received operations by Bryan ACDR ( n= 27) and ACDF ( n= 33) in the Third Hospital of Hebei Medical University between January 2005 and December 2009 were enrolled in this study. The Japanese Orthopedic Association (JOA) scores, neck disability index (NDI), visual analogue scale (VAS), Odom's scale, cervical range of motion (ROM), surgical segment ROM, heterotopic ossification (HO) and ASD were used to evaluate the clinical and radiologic results. The indices abovementioned were compared between the two groups. Results: The VAS, NDI and JOA scores at each follow-up node in both ACDR and ACDF group were all significantly improved when compared with those before operation (all P< 0.05), but there was no significant differences between the two groups (all P> 0.05). Of all, 88.9%(24/27) of patients in ACDR group and 84.8%(28/33) of patients in ACDF group achieved excellent or good results, however, there was no significant difference in Odom's scale between the two groups ( P> 0.05). At the last follow-up, the cervical ROM in ACDR group was 43.2°±8.8°, which was slightly lower than that before operation (45.7°±10.4°), the difference was not statistically significant ( t= 0.954, P= 0.345); the surgical segment ROM in ACDR group was 5.9°±3.6°, which was significantly reduced when compared with that before operation (8.8°±3.4°, t= 3.043, P< 0.01). However at the last follow-up, the cervical ROM in ACDF group was 36.4°±8.4°, which was significantly reduced when compared with that before operation (43.9°±11.1°), the difference was statistically significant ( t= 3.095, P< 0.01). Although, there was no significant difference in the cervical ROM between the two groups before operation ( t= 0.643, P= 0.523), and the difference was statistically significant at the last follow-up ( t= 3.054, P< 0.01). At the last follow-up, the incidence of HO in ACDR group was 92.6%, and the high-grade HO was 37.0%. The incidence of ASD in ACDR group was 39.5%, which was much lower than that in ACDF group (61.1%, χ(2)=4.462, P= 0.035). Conclusion: At minimum follow-up of 10 years, Bryan ACDR achieves a satisfactory clinical effect consistent with ACDF. In terms of advantages, ACDR could maintain the ROM of cervical and retain the ROM of the surgical segment, which reduces the occurrence of ASD by preserving motion.

Objective: To investigate the effects of preoperative segmental range of motion (ROM) on clinical and radiographical outcomes after artificial cervical disc replacement (ACDR) and explore whether ACDR could be indicated for patients with preoperative limited or excessive segmental ROM. Methods: From January 2008 to December 2017, patients who underwent Prestige-LP ACDR in West China Hospital were retrospectively reviewed. The preoperative and postoperative X-rays of the cervical spine were collected to measure the radiographic parameters, including cervical lordosis (CL), C(2-7) ROM, disc height (DH), disc angle (DA) and ROM at the arthroplasty level. Clinical outcomes were evaluated using the Japanese Orthopedic Association (JOA) and the Neck Disability Index (NDI) scores. The correlation between preoperative segmental ROM and postoperative clinical and radiographical outcomes were also analyzed. Results: A total of 161 patients were analyzed, with 73 males and 88 females. The mean age was (44±8) years, and the follow-up period was 34 months (12-120 months). JOA and NDI scores improved after ACDR ( P< 0.05). However, postoperative C(2-7) ROM and ROM at the arthroplasty level were comparable with preoperative counterparts (both P> 0.05). Preoperative segmental ROM positively correlated with C(2-7) ROM and ROM at the arthroplasty segment ( r= 0.213、0.271, both P< 0.05), but was negatively correlated with the change of ROM ( r= -0.534, P< 0.05). The segmental ROM was 4.0°±1.0° in the limited-ROM group (A) and 14.6°±1.3° in the excessive-ROM group (B), respectively. There were significantly more patients diagnosed with cervical spondylosis in group A than in group B (35.5% vs 10.7%, P< 0.05). The level-distribution was statistically different between the two groups. C(5/6) and C(6/7) were prone to limited motion in group A, while C(4/5) and C(5/6) were predisposed to excessive motion in group B (all P< 0.05). After surgery, C(2-7) ROM increased for 14.2°±16.8° in group A, while paradoxically decreased for 2.2°±14.4° in group B. However, C(2-7) ROM in group B was still larger than that in group A ( P< 0.05). Similarly, the ROM at the arthroplasty level increased by 3.1°±3.7° in group A, whereas the values decreased by 4.4°±4.2° in group B postoperatively. In addition, group A still had less segmental ROM than group B ( P< 0.05). The preoperative DH in group A was less than that in group B ( P< 0.05). The rates of ASD, HO, and high-grade HO in group A were all higher than those in group B but without significant differences (all P> 0.05). Conclusion: Preoperative segmental ROM has no significant effects on clinical outcomes after ACDR; it has a positive correlation with postoperative global and segmental ROM while is negatively correlated with ROM change.

Objective: To investigate the correlation between the severity of uncovertebral joints degeneration and heterotopic ossification (HO) after single-level artificial cervical disc replacement (ACDR). Methods: From January 2005 to January 2016, 70 patients who had undergone single-level ACDR in Peking University Third Hospital and had at least 5 years follow-up were included in this study. There were 35 males and 35 females with an average age of (42±8) years (range, 25-62 years). Cervical spine A-P X-rays were taken to assess the degeneration of uncovertebral joints and lateral X-rays were taken to assess the degeneration of intervertebral space. Cervical spine lateral and the flexion-extension X-rays at 5 years follow up were taken to assess HO. Degeneration of uncovertebral joints were evaluated by the classification system set-up in Peking University Third Hospital. Kellgren&Lawrence grading system was used to evaluate the degeneration of intervertebral space. HO was evaluated by the McAfee grading standards. The data were collected before surgery and at 5-years follow-up, then the correlation between degeneration of uncovertebral joints, degeneration of intervertebral space and HO was analyzed with Spearman non-parametric test. Results: The average follow-up time of 70 patients was (62.7±4.8) years (range, 52-74 months). There was a significant positive correlation between preoperative uncovertebral joints degeneration and HO after ACDR ( r= 0.585, P< 0.01). There was a significant positive correlation between preoperative intervertebral space degeneration and HO ( r= 0.557, P< 0.01). There was a significant positive correlation between preoperative intervertebral space degeneration and preoperative uncovertebral joints degeneration ( r= 0.727, P< 0.01). Conclusion: There is a significant positive correlation between preoperative uncovertebral joints degeneration and HO after ACDR.

Total lumbar disc replacement is an alternative to interbody fusion for the effective treatment of symptomatic degenerative disc disease. This paper reviewed the history of ball-on-socket type artificial lumbar disc (ALD) prosthesis, which is a typical ALD prosthesis and summarized the ALD prosthesis research progress, according to different materials such as metal-on-metal, metal-on-polymer, and polymer-on-polymer prosthesis. The structural design factors of ball-on-socket type ALD prosthesis were analyzed and its prospect of development was also presented. The purpose of this paper is to provide a theoretical reference for the design of the ball-on-socket ALD prosthesis by reviewing the current state of ball-on-socket type ALD prosthesis.

Objective: To investigate the impact of implant height on the morphology of cervical facet joints in artificial cervical disc replacement (ACDR). Methods: A finite element model of the cervical spine from C(2) to C(7) was constructed. The surgical processes of ACDR were simulated by insertion of 5 mm, 6 mm or 7 mm Prestige-LP artificial cervical discs. The morphological changes of cervical facet joints were recorded in terms of facet overlap distance, facet overlap area and facet angle. Results: The normal height Prestige-LP cervical disc could restore the natural status of the cervical spine. Compared with the intact condition, the model with ≥2 mm height implant would reduce the overall range of motion (ROM) by 19.2% in flexion, 19.4% in extension, 18.4% in lateral bending and 19.0% in axial rotation. Besides, the ROM at the surgical level reduced by 15.8% in flexion, 15.4% in extension and lateral bending and 19.0% in rotation. The upper and lower adjacent levels (C(4/5) and C(5/6)) showed more obvious changes in ROM, which reduced by 26.8% and 26.5% in flexion, 26.6% in extension, 26.5% and 26.4% in lateral bending, and 26.4% and 26.3% in rotation, respectively. The reduction of facet overlap distance, facet angle and facet overlap area with the ≥2 mm height artifact was 9.6%, 30.7%, and 17.9% respectively at the upper adjacent level, and 22.3%, 35.3% and 28.2% respectively at the surgical level, compared with the intact model.The morphology of facet joints at the lower adjacent level were slightly changed. Conclusion: The implant height selection in ACDR should be in accordance with the physiological intervertebral disc height. Artifact with ≥2 mm in height would obviously change the morphology of facet joints, thus should not be used in clinical practice.

Objective: To evaluate long-term radiographic and clinical effectiveness of total cervical disc replacement (TDR) with Prodisc-C prosthesis at a minimum of 10 years follow-up., Methods: The clinical data of 118 patients with cervical disc degeneration disease (CDDD) treated with TDR by using Prodisc-C prosthesis between December 2005 and April 2008 were retrospectively analyzed. There were 66 males and 52 females, with the age of 25-62 years (mean, 46.8 years). There were 38 cases of cervical spondylotic radiculopathy, 28 cases of cervical spondylotic myelopathy, and 52 cases of mixed cervical spondylotic myelopathy. The operative segments were C 3-7 , including 90 cases of single segment, 20 cases of continuous double segments, and 8 cases of continuous three segments. A total of 154 Prodisc-C prostheses were used during the operation. The clinical effectiveness was evaluated by pain visual analogue scale (VAS) score, neck disability index (NDI), Japanese Orthopaedic Association (JOA) score, and Odom grade before and after operation. Imaging evaluation indicators included range of motion (ROM), sagittal lordosis angle, intervertebral disc height (IDH), and prosthesis displacement, subsidence, loosening, locking, and heterotopic ossification (HO), adjacent segment degeneration (ASD), and other complications. Patients were grouped according to whether HO or ASD occurred or not, the ROM of surgical segment was compared., Results: All patients were followed up 121-150 months (mean, 135.8 months). No revision operation was performed during the follow-up period. The VAS, NDI, JOA scores and Odom grades were significantly improved at 1 week after operation and last follow-up when compared with preoperative ones ( P <0.05); VAS and NDI scores were further improved at last follow-up than those at 1 week after operation ( P <0.05); there was no significant difference in JOA scores and improvement rates between at 1 week after operation and at last follow-up ( P >0.05). The ROM of the whole cervical spine and the operative segment decreased at 1 week and 10 years after operation when compared with preoperative ones ( P <0.05), but there was no significant difference in the other time points ( P >0.05); there was no significant difference in the ROM between the upper adjacent segment (UAS) and the lower adjacent segment (LAS) at each time point after operation ( P >0.05). There was no significant difference in sagittal lordosis angle of cervical spine before and after operation ( P >0.05); the sagittal lordosis angle of operative segment increased significantly at 1 week, 6 months, 1 year, and 2 years after operation ( P <0.05). The IDH of operative segment was significantly improved at each time point after operation ( P <0.05), but there was no significant difference in IDH between UAS and LAS at each time point after operation ( P >0.05). No prosthesis displacement, subsidence, or loosening occurred at each time point after operation. There was no significant difference of the prosthetic displacement and subsidence distance between all time points after 6 months after operation ( P >0.05). At last follow-up, the incidence of prosthetic locking/fusion was 10.4%, showing no significant difference when compared with 6 months (1.9%) ( P <0.05). The incidence of upper ASD and lower ASD was 1.3% and 2.6% respectively at 1 week after operation. The incidence of upper ASD and lower ASD increased gradually with time prolonging, and there were significant differences between different time points ( P <0.05). The ROM of operative segment in ASD group was lower than that in non-ASD group at each time point after operation, but there was no significant difference ( P >0.05). HO appeared in 58.4% of the segments at 6 months after operation, and the incidence of HO increased significantly with time, which was significantly different from that at 6 months after operation ( P <0.05). The ROM of operative segments in HO group was significantly lower than that in non-HO group at 6 months, 2 years, 5 years, and 10 years after operation ( P <0.05)., Conclusion: TDR has little effect on adjacent segments, although there are some imaging complications, it has no significant effect on the improvement of overall clinical effectiveness. Prodisc-C prosthesis can provide long-term, safe, and definite clinical effectiveness in the treatment of CDDD.

Objective: To investigate the effect of Bryan cervical disc replacement on cervical curvature and replacement segment in the treatment of cervical spondylosis, and analyze its clinical efficacy., Methods: Forty-nine patients underwent Bryan artificial cervical disc replacement from August 2010 to August 2013 were retrospectively analyzed. There were 26 males and 23 females, aged from 27 to 66 years old with an average of 48.5 years. Including 21 cases of nerve root type, 16 cases of spinal cord type, 12 cases of mixed type. And 21 cases were single segment replacement, 28 cases were double segments replacement. Preoperative and postoperative pain was compared using visual analogue scale(VAS);cervical function was observed by Japanese Orthopedic Association Scores (JOA) and Neck Disability Index (NDI);cervical lordosis curvature, function spinal unit(FSU) curvature, activities of replacement and adjacent segment, FSU activity were measured by cervical X-rays. Clinical effects were evaluated by the Odom method., Results: All the patients were followed up for 18.5 to 37.3 months with an average of 33.1 months. Pvoperative VAS, JOA, NDI scores were 7.08±1.55, 5.2±1.9, 39.96±7.06 before operation, 3.76±2.33, 13.20±1.20, 25.20±6.64 at 3 months after operation, and 2.80±1.50, 14.3±1.6, 24.24±7.89 at the last follow-up. Patients at three months and the last follow-up after operation were obviously improved in their VAS, JOA, and NDI scores ( P <0.05). There was no significant difference between the scores at last follow-up and 3 months after operation. Cervical lordosis changed from (10.64±4.26)° preoperatively to (13.68±4.56) ° at the last follow-up;the FSU curvature from (5.40±0.41) °to (9.92±2.00) °at the last follow-up ( P <0.05). The range of motion of the cervical spine preoperatively, 3 month postoperatively, and at the last follow-up were(70.84±6.17)°, (60.00±6.58)°, (71.48±4.61)°; FSU activities were(12.00±0.49)°, (9.36±0.26)°, (12.52±0.33)°;the activities of replacement segment were (10.48±0.67)°, (7.24±0.34)°, (9.28±0.36)°;the activities of upper segment of replacement were (10.52±0.60)°, (8.60±0.30)°, (10.44±0.43)°;the activities of lower segment of replacement were (8.48±0.40)°, (6.56±0.36)°, (9.60±0.39)°;there were significant differences in above items preoperatively and 3 months postoperatively( P <0.05); and there were no significant difference preoperatively and at the last follow-up( P >0.05). Pharyngeal discomfort and hoarseness occurred in 5 cases, and were recovered within 2 weeks after operation;heterotopic ossification occurred in 1 case at 6 months after operation;displacement of prosthesis occurred in 1 case at 12 months after operation. Based on Odom standard to evaluate the clinical outcome, 20 cases obtained excellent results, with 27 good, 2 general., Conclusions: Bryan artificial cervical disc replacement not only generate good clinical effects, but may also restore the cervical lordosis and FSU curvature, while retaining the activities of replacement segment, and restoring overall cervical biomechanical functions., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.)

Objective: To compare the clinical effects and clinical indications between Mobi-C cervical artificial disc replacement (CADR) and MC+ anterior cervical decompression and fusion(ACDF) in treating cervical spondylosis., Methods: The clinical data of 100 patients with cervical spondylosis treated ACDF or CADR from June 2009 to June 2015 were retrospectively analyzed. There were 53 males and 47 females, aged from 38 to 70 years old. Among them, 50 cases were treated by ACDF (ACDF group), follow-up time was for 22 to 42 months with an average of (32.24±5.20) months;other 50 cases were treated by CADR (CADR group), follow-up time was for 23 to 48 months with an average of (30.40±5.66) months. Odom criterion was used to evaluate the clinical effects in two groups. JOA score, including sensory function, motor function and bladder function was used to assess the spinal cord function. Preoperative and postoperative responsible intervertebral space heights, cervical curvatures were compared by image data between two groups., Results: All incisions obtained good healing and no serious complications were found. At final follow-up, 30 cases got excellent results, 12 good, 8 fair in ACDF group;and 34 cases got excellent results, 10 good, 6 fair in CADR group;there was no significant difference between two groups(u=4.000, P =0.827). At final follow-up, the scores of sensory function and motor function were obviously improved( P <0.05), and bladder function had not obviously recovered ( P >0.05) in two groups;and CADR group in the scores of sensory function and motor function were obviously better than of ACDF group( P <0.05). There was no significant difference in preoperative intervertebral space height, cervical curvature between two groups, and at final follow-up both had different recovered. The recovery of CADR group was obviously better than of ACDF group., Conclusions: CADR can quickly recover normal action for patients and retains the movement. CADR has certain advantages in recovering cervical curvature, improveing sensory function and motor function, but it is not able to completely replace ACDF., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.)

The mechanical properties of artificial intervertebral disc (AID) are related to long-term reliability of prosthesis. There are three testing methods involved in the mechanical performance evaluation of AID based on different tools: the testing method using mechanical simulator, in vitro specimen testing method and finite element analysis method. In this study, the testing standard, testing equipment and materials of AID were firstly introduced. Then, the present status of AID static mechanical properties test (static axial compression, static axial compression-shear), dynamic mechanical properties test (dynamic axial compression, dynamic axial compression-shear), creep and stress relaxation test, device pushout test, core pushout test, subsidence test, etc. were focused on. The experimental techniques using in vitro specimen testing method and testing results of available artificial discs were summarized. The experimental methods and research status of finite element analysis were also summarized. Finally, the research trends of AID mechanical performance evaluation were forecasted. The simulator, load, dynamic cycle, motion mode, specimen and test standard would be important research fields in the future.

Objective: To evaluate the long-term efficacy and influencing factors of cervical artificial disc replacement (CADR) for patients with cervical spondylotic radiculopathy (CSR)., Methods: The data of 29 CSR patients who underwent Bryan artificial disc replacement between December 2003 and December 2007 and followed up more than 10 years were retrospectively analysed. There were 16 males and 13 females with an average age of 54.1 years (range, 40-70 years). The disease duration was 2-144 months (mean, 19.2 months). CT and MRI were performed before operation to identify the compression segments (C 3, 4 in 2 cases, C 4, 5 in 6 cases, C 5, 6 in 18 cases, C 6, 7 in 3 cases) and the compression factors. According to the compression factor, the patients were divided into 2 groups: 14 patients with cervical disc herniation were in the group A and 15 patients combined with osteophyte were in the group B. There was no significant difference in gender, age, disease duration, and compressed level between 2 groups ( P >0.05). The radiographic and clinical evaluation indexes were recorded before operation and at last follow-up. The radiographic evaluation indexes included the global cervical and segmental range of motion (ROM), loss of ROM (ROM<3°) at last follow-up, Cobb angle and incidence of local kyphosis, paravertebral ossification (PO) grading. The clinical evaluation indexes included neck disability index (NDI) and overall efficacy (Odom's score)., Results: All patients were followed up 121-153 months (mean, 130 months). The results of radiographic evaluation indexes showed that within group comparison, except that the Cobb angle of the operated level was significantly decreased ( P <0.05) in both 2 groups, there was no significant difference in global cervical ROM and segmental ROM between preoperation and last follow-up ( P >0.05). Except that the loss of ROM (ROM<3°) at last follow-up and high-grade PO at last follow-up in group B were significantly higher than those in group A ( P <0.05), there was no significant difference in other radiographic evaluation indexes between 2 groups ( P >0.05). The results of clinical evaluation indexes showed that the NDI was significantly improved in both groups ( P <0.05) at last follow-up. There was no significant difference in the NDI at preoperation and at last follow-up, the decline of NDI at last follow-up, and the overall efficacy evaluated by Odom's score between 2 groups ( P >0.05). The excellent and good rate of overall efficacy reached 100% in both groups., Conclusion: CADR has satisfied long-term efficacy in treating CSR. The maintenance of segmental mobility was better in patients with disc herniation than in patients with disc herniation and osteophyte.

Objective: To evaluate the influence of carpentry of Bryan disc, including artificial disc coverage ratio and shell angular, on long-term efficacy and complications cervical artificial disc replacement. Methods: To retrospectively analyze the clinical data of 86 patients who underwent Bryan disc replacement in Beijing Jishuitan Hospital between 2003 and 2007 (including 101 operated segments). All the patients were followed-up for more than 10 years. Mean age of the patients was (53±9) years, including 51 males and 35 females, and 71 patients underwent single-level and 15 patients underwent two-level artificial disc replacement. Artificial disc coverage ratio and shell angular were measured on postoperative natural X-ray. According to the perfectness of carpentry including 2 parameters (postoperative shell kyphosis and artificial disc coverage ratio smaller than 95%), operated levels were divided into 2 groups: 43 levels in the optimal group and 58 levels in the suboptimal group. Radiographic indexes were evaluated preoperatively and at the last follow-up, included the segmental range of motion(ROM), segmental COBB's angle, the occurrence of segmental mobility lost, segmental kyphosis and the high grade paravertebral ossification(PO). Clinical indexes including Japanese Orthopaedic Association (JOA) score, neck disability index (NDI) and Odom's criteria were evaluated preoperatively and at the last follow-up. The improvement of JOA score, NDI% decline and the satisfaction rate of Odom's criteria were calculated too. The continuous data were analyzed by independent sample t test. The grading data were analyzed by Mann-Whitney test. Results: The mean age of the optimal group was (52±7) years, including 23 males and 14 females; the mean age of the suboptimal group was (54±10) years, including 28 males and 21 females.The baseline data of two groups were comparable. There were significant differences in the segmental ROM, the segmental COBB's angle, the occurrence of segmental mobility lost, segmental kyphosis and the high grade PO between the two groups at the last follow-up ( t =5.608, 3.812, χ(2)=15.097, 18.334, 27.141, all P <0.05). The improvement rate of JOA score was 69%±39% and 66%±44%, the NDI% decline was 14%±8% and 11%±8%, the satisfaction rate of Odom's criteria was 97.3% and 83.7% in optimal group and suboptimal group, respectively; there was no significant difference in the up-mentioned indexes between the two groups( t =0.307, 1.483, Z =0.989, all P >0.05). Conclusion: The carpentry of prosthesis will influence the occurrence of segmental mobility lost, segmental kyphosis, and high grade PO with cervical artificial disc replacement in the long run. It is suggested that the artificial disc coverage smaller than 95% and the shell kyphosis should be avoided.

Objective: To evaluate the influence of the shell angle of cervical artificial disc on long-term effectiveness of cervical artificial disc replacement (CADR)., Methods: The clinical data of 71 patients who were treated with single-level CADR with Bryan prosthesis between December 2003 and December 2007 and followed up more than 10 years, were retrospectively analyzed. There were 44 males and 27 females with an age of 26-69 years (mean, 45.9 years). According to the shell angle of the cervical artificial disc which was measured on the postoperative lateral X-ray film, the patients were divided into kyphotic group (shell angle was negative) and non-kyphotic group. The following evaluation indexes before operation and at last follow-up were compared between 2 groups. Radiographic indexes included the range of motion (ROM) of cervical spine, the ROM of operated level, Cobb angle of operated level (the negative value indicated that the segmental kyphosis occurred at operated level), paravertebral ossification (PO) grades (grades 3 and 4 were high grade PO). Clinical indexes included Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), and overall effectiveness evaluation (Odom criteria)., Results: There were 24 patients in kyphotic group and 47 patients in non-kyphotic group. There was no significant difference in baseline data including gender, age, and operated level between 2 groups ( P >0.05). All the patients in 2 groups were followed up 121-165 months (mean, 128 months). There was no significant difference in preoperative ROM of cervical spine and ROM of operated level between 2 groups ( P >0.05); but the preoperative Cobb angle of operated level in kyphosis group was significantly lower than that in non-kyphotic group ( t =2.636, P =0.013). There was no significant difference in ROM of cervical spine at last follow-up between 2 groups ( t =1.393, P =0.168), however, the ROM and the Cobb angle of operated level in kyphotic group were significantly lower than those in non-kyphotic group ( P <0.05). According to the Cobb angle of operated level at last follow-up, there were 9 patients (37.5%) with segmental kyphosis in kyphotic group and 7 patients (14.9%) in non-kyphotic group, showing significant difference ( χ 2 =4.651, P =0.031). There was a significant difference in PO grades between 2 groups ( Z =2.894, P =0.004) at last follow-up. In kyphotic group, there were 10 patients (41.7%) with low grade PO and 14 patients (58.3%) with high grade PO; and in non-kyphosis group, there were 36 patients (76.6%) with low grade PO and 11 patients (23.4%) with high grade PO. There was no significant difference in JOA scores and NDI before operation and at last follow-up, and the JOA improvement rate, NDI decline, and Odom criteria score at last follow-up between 2 groups ( P >0.05)., Conclusion: The shell angle of cervical artificial disc may lead to a decrease in the postoperative segmental ROM, and an increased occurrence of segmental kyphosis and high incidence of PO.

Objective: To evaluate the long-term efficacy of cervical artificial disc replacement for patients with cervical disc herniation and degenerative cervical canal stenosis. Methods: Total of sixty-eight patients underwent single-level Bryan artificial disc replacement in Beijing Jishuitan Hospital from December 2003 to December 2007 with a minimum 10-year follow-up were retrospectively analyzed. There were 43 males and 25 females with a mean age of (46±8) years. According to preoperative CT and MRI, the patients were divided into two groups: 27 patients in cervical disc herniation group and 41 patients in degenerative cervical canal stenosis group. The evaluation indexes before surgery and at last follow-up were compared between two groups. The clinical indexes included Japanese Orthopaedic Association (JOA) score, neck disability index (NDI) and Odom's grade; and the radiological indexes included the global and segmental range of motion (ROM), Cobb's angle at operated level. The continuous variable data were analyzed by independent sample t test. Results: In cervical disc herniation group, the improvement rate of JOA score was 83%±22%, NDI% decreased by 14%±9%, and Odom's grade was excellent in 17 patients, good in 10 patients. In degenerative cervical canal stenosis group, the improvement rate of JOA was 68%±34%, NDI% decreased by 11%±7%, and Odom's grade was excellent in 19 patients, good in 18 patients, fair in 4 patients. The segmental ROM was 10°±4° and 7°±6° in cervical disc herniation and degenerative cervical canal stenosis group at last follow-up ( t =2.284, P =0.026). The global ROM was 50°±9° and 44°±14° in cervical disc herniation and degenerative cervical canal stenosis group at last follow-up ( t =2.112, P =0.038). Conclusions: Cervical artificial disc replacement has a favorable long-term efficacy in treating cervical degenerative diseases. The postoperative global and segmental ROM in patients with cervical disc herniation are better than those in patients with degenerative cervical canal stenosis.

Objective: To observe the early effectiveness of cervical disc replacement with Pretic-I, a new type artificial disc., Methods: A retrospective analysis was made on the clinical data of 10 patients who underwent single segmental cervical disc replacement with Pretic-I from June to December 2014. Among 10 patients, 4 were male and 6 were female, with an average age of 40 years (range, 27-51 years). The mean disease duration was 15.4 months (range, 4-36 months). Affected segments located at C 4, 5 level in 1 case, at C 5, 6 level in 8 cases, and at C 6, 7 level in 1 case. The visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) score, and neck disability index (NDI) were used to evaluate the clinical outcomes. Besides, the disc height and the range of motion (ROM) at operated level, and ROM of upper and lower adjacent level were measured to assess the function., Results: The operation was successfully completed in all patients who were followed up for 12 months. No complications of aggravated nerve symptoms, vertebral artery injury, esophagotracheal fistula, cerebrospinal fluid leakage, incision infection, hematoma and prosthetic loosening were observed during follow-up. The VAS score, JOA score, and NDI significantly improved at each time point after operation when compared with preoperative scores ( P <0.05). The height of intervertebral disc at operated level was significantly increased at immediate and 3 months after operation when compared with preoperative one ( P <0.05), but no significant difference was found between at 6 months or 12 months after operation and at pre-operation ( P >0.05). No significant difference was shown in the ROM at operated level, and ROM of upper and lower adjacent level between at pre-operation and at each time point after operation ( P >0.05)., Conclusion: The early effctiveness of cervical disc replacement using Pretic-I is satisfactory. The symptoms can be relieved significantly and the dynamic features of the operated level, as well as the upper and lower adjacent levels, are well preserved.

Objective: To evaluate the clinical and radiological outcomes of artificial cervical disc replacement (Prodisc-C), dynamic cervical implant and anterior cervical discectomy and fusion (ACDF) in the treatment of cervical spondylosis., Method: From May 2011 to May 2013, a total of 44 cervical spondylosis patients that received cervical disc arthroplasty (Prodisc-C), dynamic cervical implant (DCI) or ACDF were retrospectively reviewed in Orthopedics Department, Beijing Chaoyang Hospital, Capital Medical University.The patients were divided into three groups by surgical methods.Parameters as gender, age, the operation time, blood loss and average hospital stay of three groups were compared.The patients were followed 3 months, 6 months, 12 months and 24 months postoperatively.Neck disability index (NDI), Japanese Orthopaedic Association (JOA) Score and Visual Analogue Scale (VAS) were used to evaluate the clinical outcomes of the three groups.We also measured the cervical lordosis, range of motion of surgical segment and adjacent segment and height of disc at pre-op and post-op., Result: All the patients were got at least 24 months follow-up.The differences between postoperative JOA, NDI and VAS scores and preoperative scores were of statistical significance (P<0.05). There was no statistical difference in average hospital stay, JOA, NDI and VAS recovery rate (P>0.05) among three groups.But the operative time and intraoperative blood loss were statistically different (P<0.05). Compared the pre-and postoperative ROM of C2-7, operative, upper and lower levels of each group respectively, the difference between pre-and postoperative ROM of ACDF group were of statistically significant [(16.6±3.6)°, (22.3±4.6)°, (18.1±3.1)°, P<0.05], while was no statistically significant of non-fusion group(P>0.05). There was no statistically significant difference between pre-and postoperative ROM of upper and lower levels among three groups (P>0.05), but had statistically difference in operative levels [(7.0±1.0) mm, (9.2±1.5) mm, (6.8±1.4) mm, P<0.05]. And there are no serious postoperative complications., Conclusion: Two cervical non-fusion surgery and ACDF have received good clinical effects in the treatment of spondylotic myelopathy or radicular spondylosis.The artificial cervical disc replacement and dynamic cervical implant can not only recover cervical lordosis and keep the range of motion and stability of the surgical segment, but also reduce the incidence of compensatory motion at adjacent segments and will prevent from adjacent segment degeneration.

Objective: To investigate effect of Activ L total lumbar disc replacement on lumbar sagittal alignment., Methods: The imaging data of patients with degenerative disc disease received Activ L total lumbar disc replacement at Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University from March 2009 to March 2013 were retrospectively analyzed. The average age was 45.6 years(range, 35-60 years)and the surgery levels were as follows: L3-4 2 cases, L4-5 15 cases, L5/S1 5 cases, L3-4+ L4-5 3 cases, L4-5+ L5/S1 7 cases. All patients were followed up for 15 to 63 months(average, 32 months). Radiographic parameters such as lumbar lordosis angle(LL), segment lordosis angle(SL) and sacral slope angle(SS) were recorded. All the radiographic parameters were compared using one-way ANOVA at different stage. Lumbar lordosis angle of the two-level was compared with the one of one-level by using independent sample t-test before and after the operation. A partial correction test was carried out to determine the corrections between the parameters preoperatively, one month after the operation and at final follow-up., Results: One month after the operation, the lumbar lordosis angle decreased by an average of 1.8°, but there was no statistically significant(P>0.05). Compared with one month postoperation, the lumbar lordosis angle increased by an average of 6.8°(P<0.05), which also increased a lot compared with preoperation(P<0.05). The value of segment lordosis angle was rising up from preoperation to the final follow-up(P<0.05), so was the value of sacral slope angle, but there was no statistically significant between different stage(P>0.05). The lumbar lordosis angle showed no significant difference between double-level ones and single-level ones at different stage(P<0.05). The lumbar lordosis angle showed positive correlation with the sacral slope(P<0.001), however, the lumbar lordosis angle showed no corrected with the segment angle all the time(P>0.05)., Conclusions: The total lumbar disc replacement with Activ L prosthesis had contributed to maintain and improve the lumbar alignment in the short and medium term. Double- or single-level total lumbar disc replacement had no significant effect on the value of lumbar lordosis angle. The lumbar lordosis angle showed positive correlation with the sacral slope all the time with no correlation between lumbar lordosis angle and sacral slope.

Objective: To compare the related clinical outcomes of total disc replacement (TDR) versus fusion in management of lumbar degenerative disc disease (LDDD)and provide available basis for choice of surgical procedure., Methods: Computer systematically researched PubMed,EMBase, COCHRANE Library, CBMWin, CNKI, VIP databases for randomized controlled trials comparing TDR and fusion for LDDD. Data were searched until October 2013. The available statistical data was extracted after methodological assessment. The statistical soft RevMan 5.1 was used to analyze the results., Results: Total 1 658 cases of patients in 6 studies were conducted, including 543 cases of fusion and 1 115 cases of TDR. The results of Meta-analysis showed that TDR was superior to fusion in term of visual analogue scale (VAS) (OR = -3.33, 95%CI:-5.94--0.71, P = 0.01) , Oswestry disability index (ODI) (OR = -5.21, 95%CI:-7.51--2.92, P = 0.00) , complication (OR = 0.45, 95%CI:0.21-0.95, P = 0.04) . There were no statistically difference regarding operating time, blood loss and reoperation (P > 0.05). However, there was no difference in term of complication in two-year and five-year sub-analysis., Conclusion: Regardless TDR may be more effective comparable to lumbar fusion at the immediate postoperative time, vigorous evidence is still requisite to certify the result in long-term follow-up.

Objective: To explore the clinical and radiological outcomes of Discover artificial cervical disc arthroplasty and the range of motion status on adjacent segments for cervical spondylosis causing radiculopathy or myelopathy., Methods: A total of 18 consecutive patients underwent cervical arthroplasty with the Discover artificial cervical disc at our hospital. Clinical and radiological follow-ups were conducted. Their radiographic parameters of treatment and adjacent segments were evaluated at Month 1, 3, 6, 12, 18 post-operation. And the Japanese Orthopedic Association (JOA) score, visual analog scale (VAS) pain score and Odom's scale were recorded and analyzed., Results: During follow-ups over an average of 15 months, there was no occurrence of vascular injury, severe complications or prosthesis displacement and loosening. The score of JOA was 7.2±1.8 at preoperation and 16.7±4.5 at postoperation. And the score of VAS was 8.15±1.65 at preoperation and 2.03±1.12 at postoperation., Conclusion: Discover artificial cervical disc arthroplasty is efficacious and the patients recover quickly. Targeted cervical segments may be stabilized and their physiological ranges of motion preserved.

Objective: To study the microsurgical decompression combined with cervical artificial disc replacement clinical efficacy for the treatment of cervical spondylosis., Methods: From January 2006 to November 2011, 21 cases of cervical spondylosis, totally 23 intervertebral spaces, were under the microscope disc decompression and cervical artificial disc replacement. There were 11 male and 10 female patients; aged from 28 to 60 years, with an average of 46.3 years. The diagnosis included 5 cases of nerve root type cervical spondylosis and 16 cases of cervical spondylotic myelopathy. Application of Bryan prosthesis treatment of 9 patients, a total of 10 intervertebral spaces; ProDisc-C prosthesis to treat 12 patients, a total of 13 intervertebral space. Following-up Japanese Orthopedic Association (JOA), neck disability index (NDI) and visual analogue scale (VAS) scores were recorded and compared with pre-operative scores by the paired t-test., Results: The patients were followed up for 6 to 74 months, with an average of 27.7 months. Although a patient with spinal bony stenosis symptom improved, but not satisfied, and after the posterior decompression, who had a better prognosis. The remaining patients during follow-up symptoms were obvious improved, and the replacement segments were stable. There was no prosthesis subsidence and significantly offset. In 1 month post-operation and last follow-up compared with pre-operative scores, JOA (t = 9.195 and 17.070), NDI (t = 7.193 and 14.062) and VAS (t = 14.851 and 16.133) scores were significantly different (P < 0.05); and 1 month post-operation compared with last follow-up, JOA (t = 5.916), NDI (t = 7.722) and VAS (t = 4.564) scores were significantly different (P < 0.05)., Conclusions: Cervical artificial disc replacement combined with microscopic decompression surgery can completely remove the oppression of nerve tissue caused by pressure, and the efficacy is more secure.

Objective: To study the effectiveness of artificial disc replacement for cervical diseases and the adjacent segment degeneration., Methods: Between January 2008 and October 2010, 39 cases of cervical spondylosis underwent cervical disc replacement. Of them, there were 20 males and 19 females with an average age of 45.7 years (range, 32-60 years) and an average disease duration of 30 months (range, 1 month to 10 years), including 26 cases of cervical myelopathy, 11 cases of nerve root cervical spondylosis, and 2 cases of mixed cervical spondylosis. Single level disc lesion was observed in 27 cases while bi-level lesion in 12 cases. Prestige disc prosthesis was used in 9 patients, Prodisc-C prosthesis in 4 patients, and Discover disc prosthesis in 26 patients. The neurological functional recovery was assessed after operation by Japanese Orthopaedic Association (JOA) score. The range of motion of replaced segment and adjacent segments was measured (Cobb angle), and Kellgren's X-ray assessment was used to evaluate the degree of adjacent segment degeneration., Results: The operation was successfully performed in all cases, with primary healing of all the incisions. All patients were followed up from 12 to 36 months with an average of 23.1 months. JOA score was significantly improved at last follow-up when compared with preoperative score (P < 0.05), and no significant difference was observed in the Cobb angle of replaced segment and adjacent segments between pre- and postoperation (P > 0.05). According to the Kellgren's X-ray assessment, degeneration of the adjacent segments occurred in 5 cases at last follow-up, including 3 cases of degeneration from grade 0 to grade 1 or 2, 1 from grade 1 to grade 2, and 1 from grade 2 to grade 3, with a degeneration rate of 12.8%, but no significant difference was found in degeneration degree when compared with preoperative value (chi2 = 1.793, P = 0.406). No degeneration of adjacent segments occurred in 32 patients at 15 months after operation., Conclusion: Artificial disc replacement has a good effectiveness in treating cervical spondylosis, which can maintain the range of motion of the replaced segment and adjacent segments, and may have a protective effect on adjacent segment discs.

Objective: To analyze the biomechanical changes of the adjacent cervical facet joints when the angled cervical prosthesis is replaced., Methods: A total of 400 northwestern people were involved, with an age of 40 years or older. The cervical vertebra lateral X-ray films were taken, and the cervical angles were measured by professional computer aided design software, then the cervical intervertebral disc prosthesis with 10 degree angle was designed. The finite element models of C4, 5 and C4-6 segments with intact cervical discs were developed; the C4, 5 disc was replaced by the cervical prosthesis with 0 degrees and 10 degrees angle respectively; and then all models were subjected to axial loading, flexion/extension, lateral bending, and torsion loading conditions; the stress effects on adjacent facet joints after replacement were observed by comparing with that of the intact model., Results: The cervical angles were (9.97 +/- 3.64) degrees in C3, 4, (9.95 +/- 4.34) degrees in C4, 5, (8.59 +/- 3.75) degrees in C5, 6, and (8.49 +/- 3.39) degrees in C6, 7, showing no significant difference between C3, 4 and C4, 5, C5, 6 and C6, 7 (P > 0.05) and showing significant differences between the other cervical angles (P < 0.05). When C4, 5 model was axially loaded, no significant difference in equivalent shearing stress were observed in intact, 0 degrees, and 10 degrees groups; at flexion/extension loading, the stress was biggest in intact group, and was smallest in 10 degrees group; at lateral bending, the stress got the high rank in intact group, and was minimum in 10 degrees group; at torsion loading, the stress state of 10 degrees group approached to the intact one condition. When C4-6 model was loaded, the facet joint stress of the replaced segment (C4, 5) decreased significantly at axial loading, flexion/extension, and lateral bending; while no obvious decrease was observed at torsion loading; the stress of the adjacent inferior disc (C5, 6) decreased significantly at axial loading and lateral bending condition, while less decrease was observed at torsion loading, no significant change at flexion/extension condition, it approached to that of the intact one., Conclusion: The finite element analysis reveals that the biomechanical properties of 10 degrees designed prosthesis is approximate to that of the intact cervical disc, thus the 10 degrees designed prosthesis can meet the requirements of biomechanical function reconstruction of the cervical spine.

Objective: To investigate the early effectiveness of the Discover cervical artificial disc replacement in treating cervical spondylosis., Methods: Qualified for the selective standard, 24 patients with cervical spondylosis were treated between March 2010 and March 2011. Of 24 patients, 13 patients underwent anterior cervical decompression and fusion (ACDF) (ACDF group, between March 2010 and September 2010) and 11 patients underwent Discover cervical artificial disc replacement (CADR group, between September 2010 and March 2011). There was no significant difference in gender, age, disease duration, lesions typing, and affected segments between 2 groups (P > 0.05). The operative time, blood loss, and complications were recorded. Japanese Orthopaedic Association (JOA) scores, Neck Disability Index (NDI) scores, and Odom's scores were used to evaluate the postoperative effectiveness. In CADR group, the cervical range of motion (ROM) in all directions, and prosthesis eccentricity were measured before and after operation., Results: Symptoms disappeared and no complication occurred after operation in the patients of 2 groups. The patients were followed up 12 to 18 months (mean, 15.3 months) in ACDF group and 6 to 12 months (mean, 9.6 months) in CADR group. The NDI scores in CADR group were significantly higher than those in ACDF group at 1, 3, and 6 months (P < 0.05), but no significant difference was observed in JOA score improvement rate between 2 groups (P > 0.05). According to Odom's score at last follow-up, the results were excellent in 6 cases, good in 4 cases, and fair in 3 cases with an excellent and good rate of 76.92% in ACDF group, and were excellent in 9 cases, good in 1 case, and poor in 1 case with an excellent and good rate of 90.91% in CADR group, showing no significant difference (chi2 = 3.000, P = 0.223). The patients in CADR group had significant limit of cervical joint ROM in flexion and extension and right bending at 1 month (P < 0.05), but cervical joint ROM restored after 3 months. The ROMs of left bending at 3 months and 6 months were bigger than preoperative value (P < 0.05). Meanwhile, ROM in left bending were bigger than that in right bending in replaced segment and upper segment (P < 0.05), and the ROM difference between left bending and right bending in upper segment was 2 times higher than that in the replaced segment; a marked linear correlation (P < 0.05) existed between the ROM difference and prosthesis eccentricity, and prosthesis bias had bigger ROM in lateral bending., Conclusion: Discover cervical artificial disc replacement for treatment of cervical spondylosis can provide a good effectiveness and cervical postoperative movement function. As a new prosthesis, it has some merits such as simple operative steps and less complications.